On Mon, 16 Aug 2010 14:51:48 +0100, Colin Guthrie <gmane at colin.guthr.ie> wrote: > As some of you will have found out, there are some applications that > have problems relating to Xlib usage (XCloseDisplay() IIRC) when > combined with PA client libs (notably I've seen reports from VLC > relating to this). VLC media player proper works fine with Xlib and PulseAudio (although it wouldn't to have a PulseAudio expert look at the PulseAudio support). The Xlib problem can manifest itself in two different ways: * If a process calls XInitThreads() _after_ XOpenDisplay(), then XCloseDisplay() will crash trying to acquire a non-existent mutex. This is typical if you use LibVLC but fail to call XInitThreads() early in your main() function. * If a multi-thread process uses Xlib from more than one thread but never calls XInitThreads(), then depending on the phase of the moon, then race conditions might trigger crashes (typically in the form of heap corruption in my experience) depending on the phase of the moon. As regards PulseAudio, the issue comes up if libpulse is used from a different thread than Xlib. Calling XInitThreads() from main is the "official" solution. Unfortunately, there are many scenarii where this does not work. You might not have control over the main() function (e.g. the VLC plugin for Mozilla). Also Xlib might be hidden deep beneath frameworks that do not call XInitThreads, such as GTK or Qt. Since libpulse does not really need any Xlib feature not found in XCB, I humbly think switching to XCB is the best choice. XCB is thread-safe by default. Thank you for that. -- R?mi Denis-Courmont http://www.remlab.net http://fi.linkedin.com/in/remidenis
